JPS62221650A - Method for recovering unreacted acetone in production of 2,2-bis(4-hydroxyphenyl)propane - Google Patents

Abstract

PURPOSE:To purifying the titled compound synthesized from acetone and phenol as raw materials, to recover unreacted acetone with small energy consumption, by feeding a mixture containing separated unreacted raw materials to a phenol process of cumene process. CONSTITUTION:Acetone is reacted with phenol in the presence of an insoluble acidic catalyst to give a reaction product, which is distilled D1 to give a column bottom solution comprising bisphenol A and phenol as main components and a column top distillate solution comprising unreacted acetone, water and accompanied phenol and the column bottom solution 5 is sent to a bisphenol A purifying process to give high-purity bisphenol A. The column top solution 4 is fed to a neutralization process N following a cumene hydroperoxide acid decomposition process A of phenol process of cumene process and/or a previous process of a liquid-liquid separation B2 of a washing process W and the unreacted acetone is recovered according to the phenol process of cumene process.

Description

[Detailed description of the invention] This invention relates to the use of 2,2-bis(4-hydroxyphenyl)
This invention relates to a method for recovering unreacted acetone in the production of propane (hereinafter referred to as bisphenol A).

■ Bisphenol A can be used in polycarbonate resins and epoxy trees. It is produced from acetone and phenol in the presence of a soluble acidic catalyst such as hydrochloric acid or sulfuric acid, or an insoluble acidic catalyst such as a strongly acidic ion exchange resin. .

When using a soluble catalyst, there are economical problems such as removal of the catalyst, equipment material, etc., and in recent years there has been a tendency to use an insoluble catalyst.

Insoluble catalysts generally have a slow reaction rate, and attempts are made to improve the catalytic activity by modifying them with sulfur-containing compounds such as mercaptoamine and mercapto alcohol (Japanese Patent Publication No. 14721/1972, Japanese Patent Publication No. 19953/1982).
.

However, it is difficult to complete the reaction, so unreacted acetone is separated from the reaction mixture along with the produced water and some phenol, purified by distillation, and recovered for use.

For example, in Japanese Patent Publication No. 37-981, a mixture consisting of unreacted acetone, water, and phenol is separated by distillation from the reaction mixture, and acetone with a low water content and some phenol are purified and recovered using two distillation columns. .

In the first distillation column, a large amount of dry acetone is supplied to a part of the reboiler, for example, 30 parts by weight per 1 part by weight of water to be removed, and the rising acetone vapor and the above Contact is made with the mixture to strip the acetone and water and recover the phenol from the bottom of the column.

The top liquid is rectified in the second distillation column, and acetone and water are separated to a high degree. A part of the acetone separated here is recovered to the reaction system, but the remaining acetone is recycled to the bottom of the first distillation column as dry acetone.

In this method, acetone and phenol with low water content are recovered, but as mentioned above, a large amount of acetone is recycled in the distillation recovery system and is repeatedly evaporated and condensed, so the energy used is low. becomes enormous.

When bisphenol A is synthesized using a strongly acidic ion exchange resin as a catalyst, ions are generated by water flowing into the reaction zone and/or reacting, regardless of whether or not it has been modified with a sulfur-containing compound. The catalytic activity of the exchange resin is significantly reduced.

For example, even if there is no water flowing into the reaction zone, the reaction rate will gradually slow down due to the reaction product water, and in a normal batch system, the reaction rate will gradually slow down.
It takes 10 hours or more to obtain an acetone conversion rate of 5% or more, and in a continuous system, a huge amount of ion exchange resin is required to reach the same conversion rate.

For this reason, there is a limit to the acetone conversion rate, and practically 5
It is said that around 0% is good (Tokukoku Sho 36-23334
issue).

Although it is economically preferable to recover unreacted acetone for use, it is necessary to minimize the water content in the recovered acetone, so conventional techniques require complicated separation steps and a large amount of energy. .

In order to solve the above-mentioned problems, the inventors of the present invention have conducted intensive research and have completed the present invention.

That is, the method for recovering unreacted acetone in the production of 2,2-bis(4-hydroxyphenyl)propane of the present invention is to recover 2,2-bis(4-hydroxyphenyl)propane synthesized from acetone and phenol in the presence of an insoluble acidic catalyst. When refining (4-hydroxyphenyl)propane, separated unreacted acetone, water and accompanying phenol are removed from the liquid in the neutralization step and/or washing step following the cumene hydroperoxide acid decomposition step of the cumene method phenol process. It is characterized in that it is recovered in a step prior to separation.

The present invention is applied to the recovery of unreacted acetone in a method for producing bisphenol A from acetone and phenol in the presence of an insoluble acidic catalyst, and is applicable to the production of bisphenol A using an ion exchange resin. The method is not limited.

When producing bisphenol A from acetone and an excess amount of phenol in the presence of a strongly acidic ion exchange resin, the reaction is usually carried out at a gauge pressure of from normal pressure to 5 kg/cal and at 0-
It is carried out at a temperature of 120°C, preferably 50 to 100°C, and the molar ratio of phenol to acetone is 5 to 3.
A value of about 0 is considered suitable.

The reaction zone outflow mixture contains unreacted acetone, water, phenol, bisphenol A, reaction by-products, etc., and unreacted acetone is converted into a mixture containing water and some accompanying phenol through normal distillation. After separation, it is recovered in the cumene phenol process.

The cumene method funinol process consists of a cumene production process in which cumene is produced from benzene and propylene, an oxidation process in which cumene is oxidized to cumene hydroperoxide, an acid decomposition process in which cumene hydroperoxide is decomposed into phenol and acetone using sulfuric acid, The process is broadly divided into a purification process in which phenol and acetone are purified by distillation, and a recovery process in which acetone and cumene are recovered from the mixture separated and removed in each process.

More specifically, the acid decomposition process includes a decomposition process in which cumene hydroperoxide is decomposed with sulfuric acid, a neutralization process in which sulfuric acid in the decomposition mixture is neutralized and removed, and a washing process in which remaining alkali and neutralization products are removed by washing with water. It is subcategorized into. Water is added during the neutralization and washing steps, both of which are separated into liquids and removed as an aqueous phase. What is important in the present invention is that the mixture of unreacted acetone, water and entrained phenol sent from the bisphenol A process is recovered in the neutralization step and/or in the washing step prior to liquid-liquid separation.

The Nakadan group separated in the washing process consists of phenol, acetone, dissolved water, and others, and is sent to the next purification process.

The purification process consists of a crude acetone column that separates crude acetone through a series of columns, a low-boiling separation column that removes low-boiling impurities such as aldehydes from the crude acetone, and a purified acetone column that purifies pure acetone from the bottom liquid of the low-boiling separation column. , a high-boiling separation column that removes high-boiling impurities from the bottom liquid of the crude acetone column, an extractive distillation column that removes low-boiling impurities from the cumene column, and a purification column that purifies pure phenol.

Through this process, unreacted acetone and accompanying phenol are purified and recovered. Further, the water dissolved in the organic phase is removed together with cumene mainly from the top of the extraction distillation column, separated from the cumene by liquid-liquid separation, and then sent to a recovery step. In the recovery process, acetone and cumene are recovered from the aqueous phase and cumene phase separated in each process, and acetone is recycled to the purification process and cumene to the oxidation process. Note that each of the above-mentioned steps is common and does not limit the scope of the present invention.

The present invention will be explained with reference to the drawings.

FIG. 1 shows an example of a method for recovering unreacted acetone in a production example of 2,2-bis(4-hydroxyphenyl)propane of the present invention.

Phenol 1 and acetone 2 are continuously supplied to a reactor R1 filled with an uncooled acidic catalyst.

The effluent 3 from the reactor R1 is continuously extracted and sent to the distillation column D.
Sent to 1. The bottom liquid 5 containing bisphenol A and phenol as main components is sent to a bisphenol A purification step, and highly pure bisphenol A is obtained by a conventional method.

Further, the top distillate 4 is sent to the washing step of the cumene process phenol plant.

On the other hand, in the cumene process phenol plant, the reaction mixture 6 containing cumene hydroperoxide as a main component concentrated after oxidation is sent to the acid decomposer A together with acetone 23 and sulfuric acid 7 for dilution which are recycled from the purification process. ,
Phenol and acetone are produced. Decomposition mixture 8 is sent to neutralization tank N and is aqueous alkali? &, 9, the aqueous phase 11 containing unreacted alkali and neutralization products is removed in a liquid-liquid separator B1. The organic phase 12 is the top distillate 4 sent from bisphenol A.
It is also supplied to the washer W, where it is sufficiently stirred and mixed with water 13.

The effluent 14 of the washer W is sent to a liquid-liquid separator B2 where residual alkali and neutralization products are removed as an aqueous phase 16.

The organic phase 15 is sent to the crude acetone column D2, and crude acetone 17 is obtained from the top of the column. Crude acetone 17 is sent to low boiling point separation column D3
and distilled in the presence of an alkaline aqueous solution 19 to remove low-boiling impurities 20.

The bottom liquid 21 is purified by distillation in the purified acetone column D4, and pure acetone 22 is obtained from the top of the column. In addition, the bottom liquid 24 is sent to a wastewater treatment system. Note that a part of the acetone is side-cut and circulated to the acid decomposer as acetone 23 for dilution.

On the other hand, the bottom liquid 18 of the crude acetone column D2 is sent to the high-boiling separation column,
After removing high-boiling impurities 26, it is sent to extraction column D6. A mixed liquid 27 containing diethylene glycol as a main component is also supplied to the extractive distillation column, and low-boiling impurities 28 are removed from the top of the column. Is the tower bottom liquid 29 from the refined phenol tower D? The phenol 30 is distilled and purified at the top of the column to obtain pure phenol 30.

The bottom liquid 31 contains diethylene glycol and some phenol, and is recycled to the extractive distillation column D6 together with the captured diethylene glycol 32.

In the present invention, the mixture consisting of unreacted acetone, water and accompanying phenol separated from the reaction zone effluent mixture is recovered in the neutralization step and/or washing step following the acid decomposition step of the cumene phenol process. Ru.

In this process, a large amount of water is supplied for washing the neutralized mixture.For example, the composition of the organic phase obtained by liquid-liquid separation after neutralization is 38% by weight of phenol, 45% by weight of acetone,
The proportions are 6% by weight of water and 11% by weight of others, and 1 part by weight of water is supplied to 17 parts by weight of this organic phase.

The mixture recovered from the bisphenol A process is sent to a washing step along with the organic phase. In this case, most of the water newly added to the same process has been removed by liquid-liquid separation, which eliminates the need to distill and separate a large amount of water as in the past, and the amount of water to be added is also reduced to the maximum The amount of water contained in the recovered mixture can be reduced by a significant amount. For this reason, the energy burden on the phenol process side is
This means that the amount of acetone and phenol will need to be increased to a minimum.

Note that the phenol content of the mixture recovered from the bisphenol A process is as low as, for example, about 10!1 ffi%, and water cannot be efficiently removed by liquid-liquid separation. or,
Even if the phenol content is increased and liquid-liquid separation is performed, a complicated recovery process is required as described above, which is not economical.

As described above, according to the method of the present invention, unreacted acetone can be recovered more economically than before in terms of both energy consumption and equipment costs.

Great opening The present invention will be specifically explained below using examples.

(Synthesis and deacetonization of bisphenol A) Inner diameter 5c
11. Length II! A strongly acidic ion exchange resin (Amberlyst 15; manufactured by Rohm and Haas) partially neutralized with mercaptoethylamine was filled into the tubular reactor No. 1, and washed with phenol at 75° C. overnight. The filling height after washing was 80C11.

A mixture of commercially available industrial phenol and acetone (molar ratio 15:1) was fed into the reactor with the resin N temperature maintained at 75° C. at a superficial velocity of 31.71 (catalyst)·Hr. When the reaction solution was analyzed after flowing for 5 hours, the acetone conversion rate was 60.
χ, bisphenol A selectivity was 95%.

A predetermined amount of the above reaction solution was distilled in a distillation column with an inner diameter of 3.51 mm filled with 3 sm Raschig rings to a height of 751 mm to obtain a recovered acetone mixture consisting of 60% by weight of acetone, 28% by weight of water, and 12% by weight of phenol. Ta.

(Purification of acetone and phenol) The acid decomposition mixture was collected from the neutralization tank of the phenol plant, and an organic phase with a composition of 45% by weight of acetone, 38% of phenol, 6% by weight of water, and 11% by weight of other substances was obtained by liquid-liquid separation. Ta. The above recovered acetone mixture l! 20 parts by weight of this organic phase and 1.2 parts by weight of water were mixed with i parts by weight. After thorough stirring, liquid-liquid separation was carried out to prepare 20.5 parts by weight of acetone, 46.5 parts by weight of acetone, 3786% by weight of phenol, 6.0% by weight of water, and 20.5 parts by weight of other ingredients having a composition of 9.9 parts by weight. Obtained.

Next, acetone and phenol were distilled and purified using a continuous distillation column with an inner diameter of 3.5 and packed with 3 m Dixon backing to a height of 75 cs.

The organic phase after washing with water was distilled under normal pressure to obtain crude acetone from the top of the column and a mixed liquid consisting of phenol, water, and others from the bottom of the column. The distillate at the top of the column was distilled after converting a 10% by weight aqueous sodium hydroxide solution, and after removing low-boiling impurities, distillation was performed again to obtain 5.4 parts by weight of pure acetone from the top of the column. .

The bottom liquid was distilled under reduced pressure to remove high-boiling impurities, and then subjected to extractive distillation using diethylene glycol to obtain a mixed liquid containing phenol and diethylene glycol as main components from the bottom of the tower. Next, the bottom liquid was distilled again under reduced pressure to obtain 5.8 parts by weight of pure phenol from the top of the column.

(Quality of recovered acetone and phenol 61!!)
Continuous synthesis to bisphenol was carried out using the acetone and phenol obtained by the above operations as raw materials under the same conditions and operations as described above. The reaction results after 5 hours of infusion are as follows:
Acetone conversion rate 61χ, bisphenol A selectivity 94.
It was 8%.

Furthermore, when the quality of purified acetone and phenol was evaluated, they met the standard values.

,−・′

[Brief explanation of drawings]

10 is a flow diagram showing an embodiment of the method for recovering unreacted acetone in the production of 2,2-bis(4-hydroxyphenyl)propane according to the present invention. R: Reactor DI = Distillation column A; Acid decomposer N: Neutralization tank B1: Liquid-liquid separator W: Washer B2: Liquid-liquid separator D,: Crude acetone column,: Low boiling point separation column D
4: Purified acetone column DS: High boiling separation column Dh =
Extractive distillation tower: Pure phenol tower

Claims (1)

[Claims] 1) When purifying 2,2-bis(4-hydroxyphenyl)propane synthesized from acetone and phenol as raw materials in the presence of an insoluble acidic catalyst, unreacted acetone, water, and accompanying phenol were separated into cumene. 2,2-bis(4-
A method for recovering unreacted acetone in the production of (hydroxyphenyl)propane.